Lubricating greases containing salts of



United States Patent 3,125,524 LUBRICATING GREASES CONTAINING SALTS OF BORO ACIDS WITH AMINES William R. Siegart, Wappingers Falls, and Norman R- Odell and Fred C. Toettcher, Fishkill, N.Y., and Edward L. Kay, Akron, Ohio, assignors to Texaco Inc., New York, N .Y., a corporation of Delaware N Drawing. Filed Jan. 17, 1961, Ser. No. 83,179 8 Claims. (Cl. 25233.6)

This invention relates to lubricating greases and to a novel class of additives therefor. More particularly, it relates to lubricating greases containing amine salts of tetra-covalent boron acids.

Amine salts of tetra-covalent boron acids are disclosed and claimed as novel compounds in copending application Serial No. 83,175, of Edward L. Kay and Edwin C. Knowles, filed of even date herewith. We have found, in accordance with the present invention, that these compounds are employed with particular advantage in lubricating greases thickened with hydroxy fatty acid soaps, wherein they impart greatly increased dropping points and other advantages, differently from their effect in lubricating greases generally, including greases thickened with conventional fatty acid soaps.

The amine salts of tetra-covalent boron acids which are employed in the grease compositions of this invention are compounds represented by the following general formulas:

RYMBHKI R'R" x-1 I R'R" HB Ya wherein Y may be oxygen or sulfur, X is an aliphatic hydrocarbylene radical containing 2 to carbon atoms, R is a hydrocarbyl radical containing 1 to 24 carbon atoms, R is an aliphatic hydrocarbyl or halogen substituted hydrocarbyl radical containing one or more carbon atoms and preferably 8 to about 30 carbon atoms and R" and R' are hydrogen or aliphatic hydrocarbyl or halogen substituted aliphatic hydrocarbyl radicals containing 1 to 24 carbon atoms. The preferred compounds are those wherein X contains from 2 to 6 carbon atoms, R is a tertiary aliphatic hydrocarbyl group containing from 8 to 24 carbon atoms and R" and R are hydrogen.

The term hydrocarbyl radical as used herein denotes a monovalent radical. The term hydrocarbylene as used herein denotes a divalent hydrocarbon radical.

Suitable compounds of the above class include the following: octylamine salt of tetra-n-propoxy boro acid; dodecylamine salt of tetra-butoxy boro acid; ethylene diamine salt of tetra-tertiary-butoxy boro acid; hexadecylamine salt of tetra(pentachlorophenoxy) boro acid; hexylene diamine salt of tetra(nonylphenoxy) boro acid; hexadecyl salt of tetra-phenoxy boro acid; tertiary dodecylamine salt of tri-n-propyl-mono(o-chlorophenoxy)- boro acid; tertiary dodecylamine salt of tetra(o-hydroxynonylphenoxy)boro acid; and tertiary hexadecylamine salt of tri nonylphenoxy mono (p nitrophenoxy)boro acid.

Formation of the amine salts of tetra-covalent boron acids takes place readily over a wide range of conditions. The compounds may be prepared by merely mixing together a borate tri-ester and alcohol in equimolecular proportions at room temperature in the presence or absence of a solvent, and then reacting the tetra-covalent boron acid thus obtained with the theoretical amount of amine, on the basis of one amine group to each molecule of boro acid. Where the reaction is highly exothermic, the reaction mixture is preferably cooled during the reaction.

3,125,524 Patented Mar. 17, 1964 The lubricating greases to which this invention relates are those containing metal soaps of high molecular weight hydroxy fatty acids in sufficient proportions to provide at least a substantial thickening effect. The metal component may be any metal which is suitable for forming soaps employed as thickening agents in lubricating greases generally, including sodium, potassium, lithium, calcium, barium, strontium, aluminum, manganese, zinc, etc. The alkali metals and alkaline earth metals comprise a preferred class of metals for this purpose. The hydroxy fatty acid soap will usually be present in the composition in amounts from about 3 to about 15 percent by Weight, although somewhat smaller or larger amounts are also suitable, such as amounts as low as about 2 percent by weight and as high as about 30 percent by weight of the composition.

The tetra-covalent boron acid salts are ordinarily employed in the lubricating greases in amounts in about the range 0.1l0 percent by weight, although somewhat larger or smaller amounts may be employed if desired. They are most suitably employed in amounts in about the range 0.5-5 percent by weight.

Suitable soap forming acid materials which may be employed in the production of these greases include hydroxy fatty acids containing from about 12 to about 24 carbon atoms per molecule and one or more hydroxy groups separated from the carboxylic group by at least one carbon atom, and the glycerides and other esters of such acids. The preferred acids are substantially saturated acids containing from about 16 to about 22 carbon atoms and one or two hydroxy groups per molecule. Such materials may be obtained from naturally occurring glycerides, by hydroxylation of fatty acids, by hydrogenation of ricinoleic acid or castor oil, or otherwise by processes such as the catalytic oxidation of hydrocarbon oils and waxes which have been extracted and fractionated to the desired molecular range. Mixtures of hydroxy acids together with unsubstituted fatty acids may be very suitably employed, wherein the hydroxy fatty acid comprises at least about one third of the fatty acid mixture.

Lubricating oils employed in the greases include conventional mineral oils and synthetic oils, such as high molecular weight ethers, esters, silicones, etc. Suitable mineral oils include both paraffinic and naphthenic oils and blends thereof, having viscosities in the range from about seconds Saybolt Universal at F. to about 225 seconds Saybolt Universal at 210 F. A particularly suitable class of synthetic lubricating oils comprises synthetic dicarboxylic acid esters, such as di-Z-ethylhexyl sebacate, (di-secondary-amyl) sebacate, di-2-ethylhexyl azelate, etc. and polymers obtained by condensing dicarboxylic acids with glycols as disclosed in US. 2,628,- 974, as well as the sulfur analogs of such esters. Other synthetic oils which may be employed in accordance with this invention include the silicone polymers, including dialkyl silicone polymers such as dimethyl silicone polymer, diethyl silicones and mixed aryl alkyl silicone polymers such as phenyl methyl silicone polymer, having viscosities in the lubricating oil viscosity range.

The grease preparation is carried out in any suitable manner. The amine salt may be added either during the grease preparation or incorporated into the preformed grease by heating a mixture of the grease and amine salt at a moderately increased temperature with stirring, preferably following by milling. It is conveniently added during the grease preparation when the mixture has cooled to about 200 F.

The lubricating greases of this invention may also contain other additives of various types such as are commonly employed in lubricating greases, such as extreme pressure agents, anti-corrosives, anti-oxidants, etc., as well as other thickening agents, such as finely divided solids hav mg grease forming properties.

The following example is given for the purpose of further disclosing the invention.

EXAMPLE I A lubricating grease representing a preferred embodiment of this invention having the following composition in percent by weight:

Lithium 12-hydroxystearate 7.1 Amine sale of boro acid 3.0 Lubricating oil Remainder The lubricating oil is a mixture in a 3:1 ratio by weight respectively of 2-ethylhexyl sebacate and a refined paraffinic distillate oil having a Saybolt Universal viscosity of about 100 seconds at 100 F.

The amine salts of boro acids are prepared as de scribed in the said copending application. For example, the preparation of the amine salt of tri-n-propyl-monononylphenyl boro acid is carried out in the following manner: 188 grams (1.0 mol of tri-n-propyl borate are introduced into a 3 necked flask equipped with a thermometer, stirrer, dropping funnel and reflux condenser, and 220 grams (1.0 mol) of nonylphenol are added slowly. After complete mixing of the reactants, 191 grams (1.0 mol) of a high molecular weight aliphatic amine are added slowly. The amine is a commercial material sold by Rohm & Haas under the trade name of Primene 81-R consisting of tertiary alkyl primary amines in the range from C H NH to C H NH The product, obtained in a 100 percent yield, is a yellow liquid.

The grease preparation is carried out by saponifying Hydrofol acids 200 with a small excess of lithium hydroxide in the presence of a major proportion of the mineral oil contained in the grease. The saponification is accomplished by heating the mixture for 1% hours at about 317 F. The saponification mixture is then heated to 400 F. while adding 2-ethylhexyl sebacate and circulating the mixture through a shear valve at 75 pounds pressure drop while the mixture is maintained at 400 F. The mixture is cooled to 200 F. during about 2 /2 hours while additional amounts of mineral oil and 2-ethylhexyl sebacate are added. The grease is finally drawn and finished by milling in a Premier colloid mill. The amine salt of tetra-covalent boron acid is incorporated into the base grease thus obtained by heating a mixture of the grease and amine salt in suitable proportions by weight at 150 F. for thirty minutes with stirring, and then milling with one pass through a Premier colloid mill at 0.002 inch clearance. The grease thus obtained has a smooth buttery texture and very superior lubricating properties generally, including a dropping point above 400 F.

The following table shows the effect of the boro acidamine salts in improving the dropping point of the base grease.

Table I Dropping point, ASTM, F. None 366 Amine salt of mono-nonylphenoxy-tri-npropoxy boro acid 500+ Amine salt of tri-nonylphenoxy-mono-npropoxy boro acid 468 Amine salt of tetra-nonylphenoxy boro acid- 443 Borate:

In addition to the increased dropping points obtained with the boro acid-amine salts, these compounds also produce large improvements in the water absorption properties of hydroxy fatty acid soap thickened greases which normally undergo objectionable penetration changes due to water absorption.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A lubricating grease consisting essentially of a lubricating oil thickened to a grease consistency by a metal hydroxy fatty acid soap and containing about 0.110 percent by weight of a compound of the class of amine salts of tetra-covalent boron acids represented by the formulas:

wherein Y is selected from the group consisting of oxygen and sulfur, X is an aliphatic hydrocarbylene radical containing 2 to 10 carbon atoms, R is a hydrocarbyl radical containing 1 to 24 carbon atoms, R is selected from the group consisting of aliphatic hydrocarbyl and halogen substituted aliphatic hydrocarbyl radicals containing 1 to 30 carbon atoms and R" and R' are selected from the group consisting of hydrogen and aliphatic hydrocarbyl radicals containing 1 to 24 carbon atoms.

2. A lubricating grease according to claim 1 wherein R is a tertiary aliphatic hydrocarbyl group containing 8 to 24 carbon atoms and R" and R are hydrogen.

3. A lubricating grease according to claim 1 wherein the said hydroxy fatty acid soap is a lithium soap.

4. A lubricating grease according to claim 1 wherein the said amine salt of tetra-covalent boron acid is the salt of tertiary alkyl (C primary amine and monononylphenoxy-trin-propoxy boro acid.

5. A lubricating grease according to claim 1 wherein the said amine salt of tetra-covalent boron acid is the salt of tertiary allryl (C primary amine and tri-nonylphenoxy-mono-n-propoxy boro acid.

6. A lubricating grease according to claim 1 wherein the said amine salt of tetra-covalent boron acid is the salt of tertiary alkyl (C primary amine and tetranonylphenoxy boro acid.

7. A lubricating grease according to claim 1 wherein the said lubricating oil is a mineral oil.

8. A lubricating grease according to claim 1 wherein the said lubricating oil is a dicarboxylic acid ester.

Brunstrum et al. -1 Aug. 5, 1958 Ashby et al. Nov. 22, 1960 

1. A LUBRICATING GREASE CONSISTING ESSENTIALLY OF A LUBRICATING OIL THICKENED TO A GREASE CONSISTENCY BY A METAL HYDROXY FATTY ACID SOAP AND CONTAINING ABOUT 0.1-10 PERCENT BY WEIGHT OF A COMPOUND OF THE CLASS OF AMINE SALTS OF TETRA-COVALENT BORON ACIDS REPRESENTED BY THE FORMULAS: 